1. Field of the Invention
The present invention relates to a recording medium from or onto which information, such as audio and/or video and data, can be played back or recorded with copyright management. The present invention further relates to an information playback apparatus that plays back information from a recording medium while managing the copyright, and to an information recording and playback apparatus that plays back information from a recording medium and that records information to a recordable recording medium. The present invention further relates to an information playback method for playing back information from a recording medium while managing the copyright.
2. Description of the Related Art
Recently, recording media onto and/or from which digital information, such as audio and/or video and data, can be recorded and/or played back have been commercially available, such as optical discs including magneto-optical discs, hard disks (HDs), and semiconductor memories.
There are several types of optical discs, for example, a compact disc (CD) in which information, such as audio and/or video and data, is formed with pits, a magneto-optical disc in which binary data is represented by the direction of magnetization, and so forth.
A variety of CD format discs belonging to the so-called CD family, such as CD-DA (compact disc-digital audio), CD-ROM (compact disc read-only memory), CD-R (CD-recordable), CD-RW (CD-rewritable), and CD-TEXT, have been developed and become widespread. CD-DA and CD-ROM discs are playback-only media, CD-R discs are write-once media having a recording layer made of organic dye, and CD-RW discs are data rewritable media using phase change technology.
Magneto-optical discs include so-called rewritable Mini-Discs (MDs) having a diameter of 64 mm, discs having a diameter of 130 mm, and so on.
For example, if audio information recorded in a CD-DA is duplicated (copied) to a recordable disc such as a CD-R, a CD-RW, or an MD, the quality of the duplication is substantially not lowered because it is digital data, and the duplicated audio information has the same quality as that of the original audio information. Thus, the copyright of the original audio information is violated. The same applies to other recording media, such as HDs and semiconductor memories. Such a problem has not been overcome in the related art.
However, it is often inconvenient that users are prohibited from copying CD-DA audio information to a disc such as a CD-R or an MD. In some cases, users usually want to play back audio information from a CD-R or an MD while preserving the original CD-DA information for use in the event that such a disc is damaged or lost. What is essential is that users should not illegally profit by marketing multiple copies of discs and the copyright should not be violated.